Modality - the ways in which language can express grades of reality or truth - is the subject of a vast and long-established body of research. In this book, field-leader Jan Nuyts brings together twenty years of his research to offer a comprehensive, fully integrated view on areas of contentious debate within modality, from a functional and cognitive perspective. The book provides an empirically grounded, conceptual reanalysis of modality and related categories including evidentiality, volition, intention, directivity, subjectivity and mirativity. It argues for the dissolution of the category of modality and for an alternative division of the wider field of semantic notions at stake. The analysis also reflects on how to model the language faculty, and on the issue of language and thought. It is essential reading for researchers interested in the semantics of modality and in the implications of this domain for understanding the cognitive infrastructure for language and thought.